Bell Labs, the industrial research arm of Alcatel-Lucent (Euronext Paris and NYSE: ALU), has discovered that today’s ultra-broadband mobile networks can make significant energy savings and performance gains by deploying a mix of macro and small cell radio base stations.

The discovery is the result of a research project – IntelliSpektrum – which brought together in collaboration, Bell Labs, the Fraunhofer Institute for Applied Solid State Physics, the Fraunhofer Heinrich-Hertz-Institute and Intel Mobile Communications GmbH.

The project aimed to demonstrate how, even as mobile data traffic rises, and the number of devices connecting to a network increases, base stations can be dynamically adapted to better manage traffic loads and save energy without any adverse affects to end-user service quality. The research report findings included:

• Significant energy savings are possible in ‘heterogeneous’ (HetNet) mobile networks that comprise a mix of radio base stations, including Macro, Metro, Pico and Femto.
• Energy savings of more than 50% were seen in mobile networks with a high number of small cells compared to those comprised only of macro base stations. IntelliSpektrum has since transferred these results into the GreenMeter study of the GreenTouch™ initiative. This improved simulation approach will be used and distributed in GreenTouch publications.
• HetNets are able to make more efficient use of infrastructure because they can better adapt to high- and low-load traffic situations.
• While the number of radio base stations in close proximity within today’s ultra-broadband networks can create a risk of Inter-cell interference (ICI) and degrade service quality, when interference coordination is employed it not only reduces the risk of ICI but also shows gains in energy and performance – throughput gains of 10% in downlink (when the base station connects to the mobile device) and more than 50% in uplink (when the mobile device connects to the base station) were seen.

Quotes:

Marcus Weldon, President of Bell Labs & CTO Alcatel-Lucent said: “The IntelliSpektrum research project is a perfect example of how Alcatel-Lucent and Bell Labs are collaborating with other industry leaders to innovate. We are committed to research and development of energy-efficient products and technologies that offer improved network performance. Findings from the project underscore the critical importance of small cells and prove that that by deploying a mix of base station radios operators will see better energy efficiency and increased network performance – thereby improving their customers’ experience and increasing efficiency.”

Dr. Vincenzo Carrubba, scientist at the Fraunhofer Institute for Applied Solid State Physics said: “Our research is focused on making important contributions to fields that include energy, communication and mobility. We intend to use the research findings to deliver improvements in communications that make life a little easier for many people.”

Dr. Thomas Haustein, Head Wireless Networks at the Fraunhofer Heinrich-Hertz-Institute said: ”Our scientific discoveries help us deliver game-changing communications solutions. This research allowed us to show the possibilities of HetNets in terms of optimizing signal processing and wireless networks overall.”

Stefan Wolff, vice president of the Platform Engineering Group at Intel said: “Intel’s XMM™ product line delivers powerful platforms for mobile modems, smartphones, tablets and 2 in 1 convertible computers with a small PCB footprint and very low power consumption. In order to deliver an excellent user experience, future wireless networks will need more intelligent devices. This project provides some new key features in order to make that happen. This project adds to our ongoing efforts to increase power efficiency and user experience of our wireless communication SoCs.”

The IntelliSpektrum research project was funded through the German Federal Ministry of Economic Affairs and Energy. The ministry´s “IT2Green” program is targeted to develop technology to enable intelligent spectrum management and deliver energy-efficient and service-optimized access to flexible, hierarchical mobile networks.  The project concluded officially in September 2014 when the results were shared during a public workshop.

Technical Background

As part of the research project, the companies developed several items of prototype hardware and software:

• Bell Labs:
  • For the base station transmitter – a flexible dualband amplifier module, covering frequency band I (2.1 GHz) and band 7 (2.6 GHz) was used. For the final amplifier stage, different dualband capable GaN based amplifier solutions were developed, such as Class-ABJ (FhG-IAF Freiburg).
  • The base station receiver module used a GaN based wideband low noise amplifier (FhG-IAF Freiburg), combined with triband filter solutions, supporting frequency band I (1900 MHz), band 5 (800MHz) and Band 7 (2500 MHz)
  • A  neural network based amplifier linearization approach to different amplifier characteristics was developed. The linearization was applied to the Class-ABJ (IAF) amplifier investigating the potential to improve linearity and energy efficiency.
  • Management and control software was designed to dynamically adapt the base station to the network situation. It was demonstrated by controlling the flexible transceiver and adapting it to simulated scenarios.
• Fraunhofer Institute for Applied Solid State Physics:
  • For the base station transmitter (TX), a high power-efficiency and flexible final stage power amplifier (PA) module was designed using a novel dual-band Class-ABJ concept. The dual-band Class-ABJ PA module delivers high efficiency of up to 60% and output power up to 30 W while maintaining high linearity and Gain > 10 dB in the targeted frequency band I (UMTS – 2100 MHz) and frequency band 7 (LTE – 2600 MHz). Various PA designs and modules have been developed using innovative GaN (Gallium Nitride) technology.
  • For the base station receiver (RX), a linear and broadband packaged MMIC (Monolithic Microwave Integrated Circuit) LNA (Low Noise Amplifier) with very high gain G > 30 dB and low noise figure NF < 1 dB for the wide frequency band 0.4-3 GHz was designed. Various MMIC LNA concepts, again in AlGaN/GaN technology, have been implemented, packaged and characterized.
• Fraunhofer Heinrich-Hertz-Institute:
  • A reference implementation of the channel model QuaDRiGa was published under Lesser GNU Public License.
• Intel Mobile Communications:
  • A novel technology to monitor the cellular modem power consumption state in terminals together with context information on network environment, terminal state and application context.
  • Prototypes of integrated current monitor circuits. These circuits allow observervation to the actual current drain of critical cellular modem functional building blocks,
  • The accuracy of the novel monitoring technology allows the terminals to have faster reactions to network transitions. The monitors can be enabled/disabled on demand and their granularity can be adapted to provide lightweight and scalable solutions required for competitive cellular devices.

Fraunhofer Institute for applied solid state physics (f-iaf)

Fraunhofer IAF is one of the leading research institutions worldwide in the area of III-V semiconductors and diamond. We develop electric and optical devices based on modern semiconductor materials. IAF’s research and development work covers the entire value chain – from materials research through design, technology and circuits to modules and systems. The research results are used in fields such as security, energy, communication, health and mobility.

FRAUNHOFER HEINRICH HERTZ INSTITUTE

The Fraunhofer Heinrich Hertz Institute is a world leader in the development of mobile and fixed broadband communication networks and multimedia systems. From photonic components and systems to fiber optic sensor systems and real-time image processing architectures, the Heinrich Hertz Institute works together with its international partners from research and industry. Fraunhofer HHI is your competent partner for UHDTV, 3D TV, 3D displays, HDTV, gesture controlled man-machine interaction, image processing, coding and transmission, and use of interactive media.

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